The present invention relates to an optical device for detecting a magneto-optical signal and, more particularly, is directed to an optical device including a novel optical element.
In an optical device, such as a magneto-optical pickup unit of a so-called magneto-optical disc drive, optical parts are assembled in a hybrid fashion by using polarizing elements, such as a Wollaston prism, a polarizing beam splitter (PBS) or the like. Therefore, the overall arrangement of the magneto-optical pickup becomes complicated and large. Moreover, optical parts of the optical device have to be optically disposed with high alignment accuracy.
In addition, each of the optical elements is expensive and therefore it is not so easy to provide an inexpensive magneto-optical pickup.